The present invention relates to a system for air-conditioning and refrigeration. More specifically, the system provides a method and apparatus for coupling an ice-storage system to existing cooling and refrigeration devices to enhance their performance, efficiency and reduce the overall power consumption, or the cost to achieve the same operating result by reducing the power demand at peak operating periods.
An illustration and explanation of the need for expansion of the range of existing cooling devices, reduction of the operating expense or both conditions is provided in a brochure from the Electric Power Research Institute, "Supermarket Air Conditioning and Dehumidification". Although the modern convenience of the grocery store or supermarket with its air conditioned aisles, glassed or open-front freezers and display cases, and its cold-storage lockers is accepted by consumers, the costs to install, run or maintain these large cooling apparatus are not considered. Several alternative systems for supermarket cooling requirements are illustrated and discussed in the noted brochure, which includes notations on the capital and operating costs as well as a discussion of the relative advantages and disadvantages of the several systems. In this brochure, which appears to have been published in 1990, the utilization of an ice-storage or cool storage system is briefly discussed, however, there is no illustration or detailed description of an operating system and only a recognition of the potential benefits that would accrue from such a system.
Conventional cooling apparatus generally consist of stand alone devices, such as air-conditioners and individual refrigeration assemblies, each having its own ductwork for air transfer, cooling circuit and power connections. The coupling of an ice-storage apparatus to an existing cooling unit can reduce its period of operation to attain the same cooling capacity, thus reducing its energy consumption during a peak electrical cost period; or alternatively, it can be viewed that the operating range of the unit is expanded, which results in a "larger cooling capacity" unit without replacement. Further, multiple cooling devices can be connected to this ice-storage system for simultaneous operation. Illustrative of a facility with multiple cooling devices is the grocery store or supermarket, which commercial facility will frequently have an air-conditioning apparatus, a freezer or cooler with a door for goods such as icecream, an open cooler for dairy products and frozen juices, and a sub-zero cooler for storage of other foodstuffs. In a new installation, the size and configuration of some or all of the ancillary devices coupled to the ice-storage system can be reduced in size or rated capacity to deliver the same cooling capacity, which can result in an initial capital cost reduction.
Further benefits result in the ability to expand the usage of the ice-storage system to other parasitic apparatus; production of ice in the off-peak periods of electric usage, generally nighttime, reduces the cost of power to produce the requisite cooling; and, only nominal capital cost is incurred with this known basic technology.